1. Technical Field
The present invention relates generally to an improved data processing system and in particular, a method, apparatus, and computer instructions for managing configuration data. Still more particular, the present invention provides a method, apparatus, and computer instructions for recovering logical partition data in a logical partitioned data processing system.
2. Description of Related Art
A logical partitioned (LPAR) functionality within a data processing system (platform) allows multiple copies of a single operating system (OS) or multiple heterogeneous operating systems to be simultaneously run on a single data processing system platform. A partition, within which an operating system image runs, is assigned a non-overlapping subset of the platform's resources. These platform allocable resources include one or more architecturally distinct processors with their interrupt management area, regions of system memory, and input/output (I/O) adapter bus slots. The partition's resources are represented by the platform's firmware to the OS image.
Each distinct OS or image of an OS running within the platform is protected from each other such that software errors on one logical partition cannot affect the correct operation of any of the other partitions. This is provided by allocating a disjoint set of platform resources to be directly managed by each OS image and by providing mechanisms for ensuring that the various images cannot control any resources that have not been allocated to it. Furthermore, software errors in the control of an operating system's allocated resources are prevented from affecting the resources of any other image. Thus, each image of the OS (or each different OS) directly controls a distinct set of allocable resources within the platform.
With respect to hardware resources in a LPAR system, these resources are disjointly shared among various partitions, themselves disjoint, each one seeming to be a stand-alone computer. These resources may include, for example, input/output (I/O) adapters, memory dimms, nonvolatile random access memory (NVRAM), and hard disk drives. Each partition within the LPAR system may be booted and shutdown over and over without having to power-cycle the whole system.
The LPAR system may have two types of partitions, a logical type of partition and an affinity partition. Logical partitions are user-defined system resource divisions. With respect to logical partitions, a user determines the number of processors, memory, and I/O that a logical partition can have when the logical partition is active. An affinity partition is a special type of logical partition. Affinity partitions are divisions of system-defined resources that have a close physical proximity. When an affinity partition is created, the system determines the number of processors and memory that that partition can have, but the user determines the I/O requirements for this type of partition.
Configuration data for partitions are typically stored in a nonvolatile random access memory (NVRAM) for a service processor. When configuration data is needed, this data is pulled from the NVRAM to the hardware management console used to manage the LPAR data processing system. Situations occur in which this NVRAM may be cleared or corrupted. As a result, a recovery action is required for these situations. Otherwise, users are required to recreate this partition configuration data every time such a loss occurs.
Currently, a current image copy of the configuration data is saved on some regular basis to allow recovery of the configuration data when a loss is detected. Currently available recovery processes require stopping operations on the partitions while performing recovery processes because these recovery processes may overwrite configuration data for partitions currently executing. Situations occur, however, in which users are running critical or important operations on an affinity partition, and it is desirable to avoid stopping execution of that partition to restore configuration data.
Normally, profile data is merged to recreate or restore configuration data. With affinity partitions, in many cases, only a limited number of affinity partitions may be allowed. If the mirror image and the backup image have significant differences, a situation in which the number of affinity partitions may be greater in the restored profile than what is allowed or partition configuration data is inconsistent with partition types. Such situations put systems in inconsistent states. User may not able to recover from the situation. When this situation happens, users will not able to continue on using hardware management system to manage the partitions. In order to get out of this situation, users will have initialize the system which in turn stops all running partitions, delete them, and create them according to the configuration users have saved away.
With current recovery mechanism, it simply combines configuration data from backup and mirror images. With no knowledge of affinity partitions, this recovery mechanism simply overwrites the partition types that are currently defined. Because a partition type cannot be changed at runtime, the result of modifying the partition type would put the system and the partitions in undesirable and inconsistent states. This situation may indirectly cause termination of partition in order to put system back to a consistent state.
Therefore, it would be advantageous to have an improved method, apparatus, and computer instructions for recovering configuration data in LPAR systems containing affinity partitions without interrupting operations on those partitions.